Project Summary . The consumption of ?-3 fatty acid-rich foods is associated with multiple health benefits, including the prevention of cardiovascular and neurologic diseases. However, while the dietary consumption of these fatty acids often shows benefits, the use of fish-oil containing capsules and other supplements to augment the intake of ?-3 fatty acids has produced largely negative results on these health outcomes in clinical trials. The reasons accounting for the reduced benefits of the supplements are unclear, but one possibility could be a lower bioavailability of the ?-3 fatty acids in the supplements due to factors including differences in fatty acid esterification, the presence of other lipids, and the size of the oil droplets. In addition, while currently poorly studied, there may also be important differences in the presence of ?-3 fatty acids oxidation products, known as oxylipins, between the dietary and supplement sources. Importantly, these oxylipins can have biologic actions that are independent of those produced by the parent ?-3 fatty acid, so their presence or absence could alter the effects or effectiveness of a specific source of ?-3 fatty acid intake. For example, in our research we found that the treatment of the nematode C. elegans with the ?-3 fatty acid ?-linoleic acid (ALA) increases lifespan in part through the activation of the SKN-1/Nrf2 transcription factor, which coordinates responses to oxidative stress. The activation of SKN-1 occurs through the accumulation of oxidation product 9S-hydroperoxy-10E,12Z,15Z-octadecatrienoic acid (9(S)-HpOTrE) after ALA is exposed to air. Based in part on our findings, we hypothesize that the reduced health benefits of supplement versus dietary intake of ?-3 fatty acids reflects critical differences in lipid bioavailability and also the blend of oxylipins present in these two sources. Furthermore, research involving the treatment of lab animals, such as mice, with ?-3 fatty acids suffers from the same issues with the absorption and oxidation status of the ?-3 fatty acids, as well as changes in the texture and palatability of the food for the animals due to the direct addition of an oil containing the ?-3 fatty acids to a dry animal diet. To overcome these barriers, we propose to use two approaches, which are the preparative technique microencapsulation and the novel combined supplementation with oxylipins, to improve the absorption, palatability, and activity of ?-3 fatty acids with the immediate goal of enhancing the supplementation of mice diets. In particular, we will prepare and then compare diets containing ALA in microencapsulated form or diets containing microencapsulated ALA along with one of two microencapsulated oxylipins also added on outcomes including changes in gene expression and the brain injury produced in an experimental stroke model. The research will be carried out by a team including members with expertise in synthetic chemistry, microencapsulation, lipidomics, and stroke research. If this approach is successful, microencapsulation can be used in the production of novel supplements for human use, including the delivery of optimized blends of specific oxylipins along with the ?-3 fatty acids.